A conventional stator having two or more polarities shown in FIG. 3 comprises a stator 10, usually made of silicon steel plates, and two coil 20 in deposited in respective coil holes 10 formed in the stator 10. The coils are usually hand wound, in prior art systems, to be fit into the coil holes 101.
This manufacturing process of the conventional stator has drawbacks as follows:
1. The coils cannot be made tight enough, owing to manual winding operation, and the material for the coil may then be wasted;
2. Manual winding of coils takes tie, and each manufacturing operation is impossible to speed up;
3. Quality of the coils cannot be kept at a consistent level, because of the manual winding operation; and,
4. The stator is mostly made of laminated silicon steel, by means of pressing, so the coils are not easily fit into the coil holes.